Question

I’m trying to create a query that groups by a field in the first table, sums a first table field, and includes a single field from a second. I keep getting an error when attempting to refer to a field from the joined table.

Table1: Users

Id
DisplayName

Table2: TimeEntries

WeekEnding
UserId
Hours

Query:

from u in Users
join t in TimeEntries on u.Id equals t.UserId
group t by new {t.WeekEnding, t.UserId } into g
select new {WE = g.Key.WeekEnding, User = g.Key.UserId, 
HoursTotal = g.Sum(s => s.Hours), DisplayName = g.First(n => n.DisplayName)}

I’ve tried many things but “DisplayName” is not a valid field.
Any help on this will be greatly appreciated. Thank you.

Answer 1

Here’s a couple options.

from t in TimeEntries
group t by new {t.WeekEnding, t.UserId } into g
let firstT = t.First()
select new
{
  WE = g.Key.WeekEnding,
  User = g.Key.UserId
  HoursTotal = g.Sum(x => x.Hours)
  DisplayName = firstT.User.DisplayName
}


from t in TimeEntries
group t by new {t.WeekEnding, t.UserId } into g
let user = (from u in Users where u.UserId == g.Key.UserId select u).Single()
select new
{
  WE = g.Key.WeekEnding,
  User = g.Key.UserId
  HoursTotal = g.Sum(x => x.Hours)
  DisplayName = user.DisplayName
}